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Introduction |
| Mitsubishi Engineering Co., Ltd.
(MRE) has been engaged in the engineering and construction of synthetic
fiber manufacturing plants for many years. We have engineered eight
dry spinning spandex plants in China, three in Japan, and three
in Taiwan. We offer unique, market-leading fiber-production support
services, applying our extensive expertise from initial plant engineering
to day-to-day operation. |
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| Yarn guide |
Solvent recovery
unit; photo shows owner's staff with MRE staff |
Utility piping |
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| Spandex products |
Utility piping |
Spinning tubes
and control panel |
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| Operation room |
Utility piping |
Solvent recovery
unit |
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| Winding room |
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Features of MRE spandex |
(1) Excellent elasticity
(2) Excellent heat resistance
(3) Can be dyed at 130 centigrade with regular polyester
(4) Good uniformity of stress for warp knitting and circular knitting |
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| Experience in Spandex Dry-Spinning |
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| Between 1988 and 2001, MRE completed construction of ten Spandex dry-spinning plants for four companies (one each in Japan and Taiwan, and two in China). Two further plants are currently under construction for the same two Chinese customers. The Company has provided engineering, procurement and construction services for all these plants, and additionally, commissioning supervision services for seven of them. |
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| MRE's Experiences in Spandex Dry Spinning Plant |
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Client
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Country
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Spinning Process |
Scope |
Completion |
| A Company |
Japan |
Dry (F) |
EPC |
1988 |
| A Company |
Japan |
Dry (F) |
EPC |
1994 |
| B Company |
Taiwan |
Dry (F) |
EPSV |
1994 |
| B Company |
Taiwan |
Dry (F) |
EPSV |
1998 |
| A Company |
Japan |
Dry (F) |
EPC |
2001 |
| C Company |
China |
Dry (F) |
EPSV |
2001 |
| D Company |
China |
Dry (F) |
EPSV |
2001 |
| B Company |
Taiwan |
Dry (F) |
EPSV |
2001 |
| F Company |
China |
Dry (F) |
EPSV |
2003 |
| F Company |
China |
Dry (F) |
EPSV |
2003 |
| G Company |
China |
Dry (F) |
EPSV |
2004 |
| G Company |
China |
Dry (F) |
EPSV |
2004 |
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Process Description |
| (1) Polymerization |
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The raw materials PTMG (polyoxytetramethylene
glycol) and MDI (diphenylmethane diisocyanate) are polymerized in
the prepolymer reactor to form prepolymer. The prepolymer is supplied
to the polymer reactor and dissolved with DMAC (dimethyl acetamide).
Additives are supplied to the prepolymer solution and polymerized
at a controlled temperature. |
| (2) |
Spinning: Stable dope stream, smooth solvent
vaporization, forming of good round cross-section of fiber.
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The dope is precisely metered
and discharged by a gear pump mounted on an individual spinning tube,
and extruded through nozzles into the spinning tube. In the spinning
tubes, extruded dope streams are dried in a high-temperature inert
gas flow, vaporizing the solvent and forming spandex fibers. Solvent
vapor and vent gas are fed to a scrubber and absorbed into a solution
for recovery. |
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| (3) Winding |
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Spandex multi-fibers are gathered and
twisted in the air jet nozzle, and wound on paper tubes with finishing
oil applied to avoid sticking and obtain smoothness. |
| (4) Solvent Recovery |
| Standard
component of recovered |
| solvent DMAC(dimethyI
acetamide) |
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| Water content
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Less than 200 ppm |
| Acetic
acid : |
Less than 100 ppm |
| Total amine
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Less than 10 ppm |
| Electric
conductivity : |
Less than 15 s/cm
(20% solution) |
| PH : |
4.5-6.0 (20% solution) |
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Solvent solution is fed
into the solvent recovery process and separated by distillation into
pure solvent and water. Recovered solvent is recycled into the polymerization
process. The usual recovery rate of DMAC is over 98%. |
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| Standard MRE spandex specification |
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| Item |
Specification |
| 20d |
40d |
70d |
100d |
| Tenacity (g/d) |
0.9~1.0 |
0.9~1.0 |
0.7 |
0.7~0.9 |
| Elongation (%) |
 450 |
450 |
450 |
480 |
Heat resistance*1
1) Tenacity retaining (%)
2) Strain retaining (%) |
70
 55 |
70
55 |
70
55 |
70
55 |
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*1 After heat treatment, test for 45 seconds under 100% stretched in
170 centigrade |
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| Process
Block Flow |
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